1. Field of the Invention:
The present invention relates to mechanical gearing apparatus. More specifically, the present invention relates to apparatus which limit the excursion of a pivoted mass to a prescribed angle.
While the present invention is described herein with reference to an illustrative embodiment for a particular application, it will be understood that the invention is not limited thereto. Those of ordinary skill in the art, having access to the teachings provided herein, will recognize additional modifications, applications, and embodiments within the scope of the invention.
2. Description of the Related Art:
Antenna pointing systems are exemplary of the many applications in which it is desirable to control the angular excursion of a pivoted mass. Where the antenna must operate in close quarters, there is a requirement that the compound angular excursions of the antenna be mechanically limited to prevent impact damage to the system.
Common methods for limiting compound angles include peripheral bumper rings and like methods of direct contact between the device being positioned and the adjacent support structure. This typically imposes significant weight and cost penalties on the system.
For example, one approach provides for a bumper ring on the antenna adapted to engage an associated stop ring attached to the frame. To avoid significant performance degradations in the pointing of the antenna, the weight of the bumper ring must be minimized. This typically requires an elaborate and expensive manufacturing process by which unnecessary mass is removed from the ring while retaining stiffness.
In addition, the ring mass imposes significant mass requirements on the antenna. That is, the antenna must be sufficiently strong to carry the weight of the ring and to handle the associated dynamic mass moments of inertia. This militates against the use of other more lightweight antenna designs which in turn forces the use of heavier bumper rings and etc..
There is therefore a need in the art for an alternative means for controlling the compound angular excursion of pivoted masses which limits the additional supportive weight and mass moment of inertia requirements on the system.